Effective crystal field and Fermi surface topology: a comparison of d- and dp-orbital models
Effective crystal field and Fermi surface topology: a comparison of d- and dp-orbital models
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有效晶体场和费米表面拓扑：d 和 dp 轨道模型的比较
DOI：
10.1103/physrevb.88.195116
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发表时间：
2013
影响因子：
3.7
通讯作者：
A. Toschi
中科院分区：
文献类型：
--
作者：
N. Parragh;G. Sangiovanni;P. Hansmann;S. Hummel;K. Held;A. Toschi
多轨道相关材料中的有效晶体场可以通过电子相关性来增强或减小，这对费米表面的拓扑结构以及这些系统的物理性质具有重要影响。在这方面，最近的局域密度近似加上动力学平均场理论的研究镍基异质结显示矛盾的结果，这取决于是否包括较少correlatedorbitals或没有。我们调查这个问题的起源，并确定控制这些系统的费米表面特性的关键参数。没有理论，模型是四分之一填充，而当理论被包括在内时，模型迅速向半填充移动。这意味着当地的洪德交换，而不是不重要的前一种情况下，可以发挥主导作用，在控制轨道极化的扩展基组有利于形成一个更大的本地磁矩。
The effective crystal field in multiorbital correlated materials can be either enhanced or reduced by electronic correlations with crucial consequences for the topology of the Fermi surface and, hence, on the physical properties of these systems. In this respect, recent local density approximation plus dynamical mean-field theory studies of Ni-based heterostructure have shown contradicting results, depending on whether the less correlatedorbitals are included or not. We investigate the origin of this problem and identify the key parameters controlling the Fermi surface properties of these systems. Without theorbitals, the model is quarter-filled, while themanifold moves rapidly towards half-filling when theorbitals are included. This implies that the local Hund's exchange, while rather unimportant for the former case, can play a predominant role in controlling the orbital polarization for the extended basis set by favoring the formation of a larger local magnetic moment.